There have, however, been reports of adverse effects such as stomach upset, infections and allergic reactions in kombucha tea drinkers. Kombucha tea is often brewed in homes under nonsterile conditions, making contamination likely. If ceramic pots are used for brewing, lead poisoning might be a concern — the acids in the tea may leach lead from the ceramic glaze.

i'm fermenting my own SCOBY (symbiotic culture of bacteria and yeast) in my cupboard... it's pretty thick at the moment and has grown in layers to cover the entire surface area of my jar. it's pretty fragrant and seems potent. effervescent and revitalising. planning to put the SCOBY in a new batch of tea and leave it to ferment again for another 30 days...